%I #4 Dec 21 2015 12:30:51
%S 1,20,77,117,278,1959,11044,36730,123887,598383,2919993,11429093,
%T 43919671,194434626,880889564,3627851352,14690154222,63196827262,
%U 276336307138,1159331148853,4807640087709,20468995961561,88006303609494
%N Number of 3Xn integer arrays with each element equal to the number of horizontal, diagonal and antidiagonal neighbors exactly one smaller than itself.
%C Row 3 of A266131.
%H R. H. Hardin, <a href="/A266133/b266133.txt">Table of n, a(n) for n = 1..210</a>
%H R. H. Hardin, <a href="/A266133/a266133.txt">Empirical recurrence of order 77</a>
%F Empirical recurrence of order 77 (see link above)
%e Some solutions for n=4
%e ..1..1..1..1....1..2..0..0....2..1..1..2....1..2..0..1....2..1..2..0
%e ..1..0..0..2....1..0..0..0....0..1..1..0....1..0..2..0....1..1..0..0
%e ..0..2..1..1....1..1..2..1....2..1..1..2....1..1..0..0....1..0..2..1
%Y Cf. A266131.
%K nonn
%O 1,2
%A _R. H. Hardin_, Dec 21 2015
